April 30, 2015570-Trichodesmium-erythraeum_FWC-Fish-and-Wildlife-Research-Institute_Flickr-CC-BY-NC-ND-2.0 The golden-brown surface mats that indicate a Trichodesmium erythaeum bloom have led to them being called “sea sawdust.” (Image by FWC Fish and Wildlife Research Institute via Flickr CC BY-NC-ND 2.0)